Evaluation of the toxicity of food additive silica nanoparticles on gastrointestinal cells

Abstract

Silica nanoparticles (NPs) have been widely used in food products as an additive; however, their toxicity and safety to the human body and the environment still remain unclear. As a food additive, silica NPs firstly enter the human gastrointestinal tract along with food, thus their gastrointestinal toxicity deserves thorough study. Herein, we evaluated the toxicity of food additive silica NPs to cells originating from the gastrointestinal tract. Four silica NP samples were introduced to human gastric epithelial cell GES-1 and colorectal adenocarcinoma cell Caco-2 to investigate the effect of silica sample, exposure dose and exposure period on the morphology, viability and membrane integrity of cells. The cell uptake, cellular reactive oxygen species (ROS) level, cell cycle and apoptosis were determined to reveal the toxicity mechanism. The results indicate that all four silica NPs are safe for both GES-1 and Caco-2 cells after 24-h exposure at a concentration lower than 100 µg ml(-1) . At a higher concentration and longer exposure period, silica NPs do not induce the apoptosis/necrosis of cells, but arrest cell cycle and inhibit the cell growth. Notably, silica NPs do not pass through the Caco-2 cell monolayer after 4-h contact, indicating the low potential of silica NPs to cross the gastrointestinal tract in vivo. Our findings indicate that silica NPs could be used as a safe food additive, but more investigations, such as long-term in vivo exposure, are necessary in future studies.

Nanoparticles in Daily Life: Applications, Toxicity and Regulations

“…37,39 Scientists have evaluated the toxicity of SiO 2 NP as a food additive on gastrointestinal cells, indicating their safety as food additive, but suggested the necessity of long-term in vivo studies to confirm their safety profile. 40 Recently, researchers have reported that interactions between food additive SiO 2 NPs and food matrices were highly dependent on the type of food component. 41 Moreover, the experimenters have suggested that toxicity of SiO 2 NPs depends on size, dose, and cell type.…”

Biocompatibility of cerium dioxide and silicon dioxide nanoparticles with endothelial cells

“…CeO 2 , a rare-earth lanthanide element oxide, is mainly used in slurries for silicon wafer planarization [1–2], as automotive fuel additives to improve the efficiency of combustion [3–4], and as automobile catalytic converters [5]. SiO 2 nanoparticles are employed in the fabrication of electric and thermal insulators [6], as drug-delivery systems in nanomedicine [7–8], as anticaking and thickener agents in food production [9–10], as well as in cosmetics, drugs and printer toners [11]. …”

Applications and Safety of Nanomaterials Used in the Food Industry

“…The toxicity of amorphous silica nanoparticles has been assessed both at the cellular level and in animal models. For example, on the basis of the results of a study using human gastric epithelial GES-1 cells and colorectal adenocarcinoma Caco-2 cells, Yang et al suggested that silica nanoparticles (200-450 nm) may arrest the cell cycle and inhibit cell growth but they do not induce apoptosis or necrosis 54) . We previously demonstrated that silicon was not detected in the liver or blood of mice after a 28-day daily oral exposure at a total dose of about 3.5 g silica particles/kg body weight, and that none of the particles tested showed toxic biological effects 36) .…”